This project focuses on etiology and treatment of marital sexual dysfunction. One study involves an attempt to identify factors which influence the outcome of treatment. The factors of marital and sexual adjustment, personality, life history, and psychophysiologic arousal patterns will be studied to identify factors which predict success or failure of therapy. A second study is focused on the etiology of marital sexual function and dysfunction. Comparison of a non-patient normal population and our clinical population will be made on life history, personality, behavioral, and physiological variables hypothesized to be factors in etiology. A third study will be the five year follow-up of couples who previously contacted this program for treatment of marital sexual dysfunction. These couples include treatment successes and failures, couples who were offered treatment but declined to enter therapy, and those couples who were not offered treatment. Thus, stability of therapeutic gains over a long-term period will be assessed, as well as the natural history of dysfunctions not treated or treated unsuccessfully. Additionally, data on the effects of dysfunction on subsequent life adjustment will be gathered. A fourth study will be an exploration of the factors involved in an increasingly prevalent marital disorder -- the syndrome of low sex drive in males. The variables of psychiatric symptomatology, life history, personality, marital adjustment, and sexual behaviors and fantasies, will be studied to identify the psychological factors in low sex drive. Blood levels of testosterone (bound and unbound fractions), estrogen, prolactin, luteinizing hormone, and cortisol will be determined, both at rest and in response to erotic stimuli (films and audio tape), to clarify hormone-behavior relationships in sex drive. Medical evaluation and monitoring of nocturnal penile tumescence will also be undertaken. These studies have practical significance for the planning of health care delivery systems, and theoretical significance in furthering our understanding of the etiology of marital dysfunctions, and in identifying effective treatments particularized to certain types of patients.